Kate and Gerry McCann, the parents of missing four-year-old Madeleine McCann, are backing a scheme to trace missing children using social-networking websites.
The McCanns this weekend welcomed the initiative by charity Missing People, which will mean Facebook users can view details of missing youngsters on their own pages. They are also supporting a similar scheme using the Bebo social-networking site.
Missing People has set up an application for Facebook users to download, which will mean information on current appeals will be displayed on their homepage.
In a statement about the Facebook application the McCanns said: "We strongly support and encourage this new initiative to use Facebook to increase awareness of missing children.
"Using the power of social media in this way will undoubtedly capture the attention - and hopefully the help - of a younger population who are a hugely valuable and resourceful group.
"We would urge the millions of Facebook users around the world to keep looking and to do what they can to help bring these children home."
Missing People chief executive Paul Tuohy said: "If every Facebook user downloaded our BT-powered application, millions of people internationally could see an appeal that could help us to reunite a family."
Missing People is also joining Bebo's "Be Cause", an internet site which gives information for young people about charities and campaign groups, to publicise its 24-hour Runaway Helpline.